Science Travel

The narrow road up Mauna Kea leads to the deep sky

There's a unique gateway on earth, a portal to the most distant reaches of the cosmos. It's a place where ancient light, snared at last after traveling for billions of years, whispers tales from the dawn of time. The gateway lies in the middle of the Pacific Ocean on the big island of Hawaii, and it's called Mauna Kea, a sea-born volcano dormant now for about 40 centuries. Gracing its 13,796-foot summit are the magnificent trappers of primeval light: 11 observatories, including the two Keck telescopes, the most powerful in the world. They are the highest astronomical outposts on the planet, above 40 percent of Earth's atmosphere and 90 percent of its water vapor. On a good night, their view of the cosmos rivals or even surpasses that of the Hubble Space Telescope. Their combined light-gathering power exceeds the Hubble's by 50 times.

Even though these peerless observatories are generally closed to the public, if you travel to Mauna Kea you can still experience a view of the night sky unmatched anywhere on Earth. From a vantage point 19 degrees above the equator, the summit provides a glimpse of every star in the Northern Hemisphere and 85 percent of the southern sky. And every night of the year, a visitors' center at an elevation of 9,300 feet sets up several telescopes freely available to anyone intrepid enough to make the trek up Mauna Kea's flank.

But like many worthwhile endeavors, the journey is not an easy one. The road to Mauna Kea's summit is dangerous: steep, narrow, winding, and mostly unpaved past the visitors' center. Only one of the island's rental-car companiesHarper's in the town of Hilolets you drive on the mountain, where a four-wheel-drive vehicle is essential. And with every upward mile on that road, the air gets increasingly thin. Astronomers who work on Mauna Kea make a point of doing any important calculations at lower altitudesoxygen deprivation makes for fuzzy thinking at more than two miles above sea level. For most casual visitors, the best way to get to the mountaintop is to let someone else drive. At least two companies offer guided tours in four-wheel-drive vans. The one I choseMauna Kea Summit Adventuresprovides heavy parkas because the temperature on the mountain can dip to freezing by late afternoon. They also pack a telescope in the van and offer an hour of stargazing after a sunset visit to the summit.

My trip up the mountain began just a few feet above sea level, which is already more than 18,000 feet above Mauna Kea's base. Measured from its roots on the seafloor, Mauna Kea is the tallest mountain on Earth, rising to 32,000 feet, more than 2,000 feet higher than Everest. The massive volcano makes up about a quarter of the island's mass and dominates the entire northern horizon. As my tour group drove up the mountain, we passed through nearly every type of ecological zone that exists on the planet, from forest to grassland to glacial moraine. Because Mauna Kea blocks the easterly trade winds, the west side of the island gets only nine inches of rain a year; the east coast of Hawaii gets 150 inches annually, making it one of the wettest spots anywhere in the United States.

Click on the image to enlarge (20k)

Viewed from the roof of the James Clerk Maxwell observatory, the Mauna Kea summit is dotted with telescopes. On the left are two of the biggest light gatherers: Subaru (cylindrical top) and Keck I (domed top).Photograph courtesy of Robin Phillips/Joint Astronomy Centre.

En route to the summit, our group stopped at the visitors' center, named for Ellison Onizuka, the Hawaiian astronaut who died when the space shuttle Challenger exploded in 1986. The staff had already set up its telescopes for the night and was just about to remove a Celestron telescope equipped with filters for viewing the sun. Taking a quick peek through that telescope, I saw sunspots and a solar prominence arcing over the edge of the sun. After spending half an hour at the visitors' center adjusting to the altitude, we left the paved road for a very rough drive across graded lava, intentionally kept unimproved to discourage tourists. As we lurched over the road, Buck Pelkey, our guide, mentioned that some very delicate pieces of equipment had to be hauled over this same route, including the largest single piece of glass ever made: the $97 million, 27-foot-wide mirror of the Japanese Subaru telescope, transported on a specially built truck equipped with ground-sensing radar.

Cloud tops were now a few thousand feet below us. Through occasional breaks we could see the soft green valleys that lay between us and Mauna Loa, an active volcano to the south that at 13,681 feet nearly matches Mauna Kea in height. We reached the summit just before sunset. Six gleaming domes extended in a semicircle away from us on a dark brown volcanic ridge; five others were hidden from view slightly below. Trade winds that had blown across the open ocean for thousands of miles, unruffled by any landmass, encountered their first obstacles: our faces. Astronomers value those smooth flows; the low turbulence helps create the best astronomical viewing conditions on Earth. Indeed, as I watched the first stars appear, they twinkled not at all.

As the sky darkened, the observatory domes opened up one by one, like huge, cyclopean eyes slowly blinking into wakefulness. The domes opened noiselessly, so quietly that even though I stood right below Britain's James Clerk Maxwell Telescope, I heard nothing as its shutters parted.

Soon it was too cold to remain at the summit, and we crowded back into the van and drove down about 4,000 feet to set up our own eight-inch Celestron beside a small cinder cone. We saw Jupiter and four of its moons, tiny and delicate as sequins, and Saturn and its rings. The North Star and the Southern Cross hung in the same sky, a view few sky watchers have ever seen. Buck Pelkey pointed out the star Arcturus, which was directly overhead. Ancient Polynesian navigators used the star to guide them to Hawaii. They called it Hokule'a, star of joy. As we huddled with cups of hot chocolate, Hokule'a hovered above Mauna Kea, a mountain sacred to Hawaiians and astronomers.

Looking back at the summit, now a dark mass against the starlit sky, it seemed clear that the telescopes there represent something far more profound than technological prowess. Just as France's great cathedral at Chartres expresses the spiritual essence of medieval Europe, Mauna Kea's observatories embody some of the noblest aspirations of our culture. The observatories serve no worldly end; they exist solely to help us better understand the universe. Each is a high temple of our time, our Stonehenge, our Parthenon. Anyone touched by the wonder of astronomyor anyone who hasn't beenshould make the pilgrimage to Mauna Kea.

Mauna Kea's Eyes on the Sky

Keck I and Keck II, housed in separate but neighboring domes, each have a 33-foot-wide segmented mirror, making them the largest optical and infrared telescopes on Earth.

Subaru, the Japanese national telescope, features the world's largest single-piece mirror, which stretches 27 feet across.

Gemini possesses a twin on Cerro Pachón in the Andes Mountains of Chile. Both have mirrors nearly as large as the Subaru's, and together they provide seamless coverage of the Northern and Southern Hemispheres.

The United Kingdom Infra-Red Telescope, the world's largest dedicated infrared scope, covers everything from comets to galaxies.

The Caltech Submillimeter Observatory, the Submillimeter Array, and the James Clerk Maxwell Telescope all study light with submillimeter wavelengthslonger than infrared, shorter than radio waves. The Maxwell telescope has found hints of planet formation around very young stars.

The Canada-France-Hawaii Telescope, another immense optical/infrared instrument, has made detailed observations of the Kuiper belt, a ring of asteroids in the outer solar system.